Motor-controlling device



Nov. 4, 1930. c. J. ANDERSON ,5

MOTOR CONTROLLING DEVICE Filed June 29, 1928 2 Sheets-Sheet l NOV. 4,1930. Q ANDERSON 1,780,612

MOTOR CONTROLLING DEVICE Filed June 29, 1928 2 Sheets-Sheet 2 far/ of4770 823907?- Patented Nov. 4, 1930 PATENT @FFEE CARL J". ANDERSON, OFCHICAGO, ILLINOIS MOTOR-CONTROLLING DEVICE Application filed June 29,1928.

My invention relates to devices for controlling the operations ofreversible motors, and has for its object improvements in such devices.

In the accompanying drawings Fig. 1 is a front elevation of acontrolling device illustrating my invention;

Figs. 2 to 5, inclusive, are sections on correspondingly marked lines ofFig. 1; and

Fig. 6 is a diagram of the circuits involved.

Mounted upon a slate 9 is a solenoid 10 having an armature 11, saidsolenoid being preferably supported in a vertical position so that thearmature will fall by gravity to its 5 lower position as shown in Figs.1, 2 and 3.

Supported near the lower part of the slate 9 are standards 12 and 13which carry a horizontal shaft 14, and secured on this shaft is afour-toothed ratchet wheel 15. Pivoted upon the shaft 14, and adjacentto the ratchet wheel 15, is an arm 16 which carries a pawl 17 adapted toengage the teeth of the ratchet wheel. On the arm 16 is a lug 18, andbetween this lug and the pawl 17 is a spring 19 which serves to pressthe pawl into contact with the ratchet wheel.

Pivoted in the lower hollow end of the armature 11 is a connecting rod'20, the lower end of which rod is connected to a pin 21 carried in theend of the arm 16, said pin 21 serving also as a pivoting pin for thepawl 17. The construction is such that when the armature 11 is attractedby energizing the solenoid 10, the arm 16 is moved to cause the pawl 17to advance the ratchet wheel one step, and'consequently to advance theshaft 14 and parts carried thereby. When the solenoid is de-energized,the armature falls back to its lower position and carries the pawl backinto a position adapted to engage the next tooth of the ratchet wheelwhen the solenoid is again energized. This lower position of thearmature is determined by a pro jection 22 on the standard 13, whichprojection serves as a stop as shown in Figs. 2 and 3.

Secured to the slate 9 are three brackets 23, 24 and 25, and pivoted tothese brackets are contact levers A, B and C. Under the upper ends ofthese levers are contact blocks, one of which is shown at in Fig. 3.Under the Serial N0. 289,232.

lower ends of the levers, and near the brackets to which the levers arecentrally pivoted, are springs 26, one of which is shown in Fig.

3. These springs act to normally press the upper ends of the levers intocontact with their respective contact blocks.

The lower ends of the levers A, B and O are provided with rollers 27which are adjacent to cams 28, 29 and 30 secured upon the the shaft- 14.These rollers are made of insulating material to prevent electricalconnection being made from one lever to another by way of the shaft 14.

The cams 28, 29 and 30 act to depress the lower ends of the contactleversA, B and C against the action of their springs 26 so as to liftthe upper ends from their respective contact blocks or points. Later thecams release said levers so that the springs 26 may operate to closeelectrical connections as will be explained hereinafter.

Figs. 3, 4 and 5 represent the cams 28, 29 and 30 in their normalpositions, which are the positions in which all contact levers arelifted from their contact blocks. Cam 28 has on it two projections,between which projections are two depressions or parts cut away. As aconsequence, a complete revolution of the cam will twice lift the leverA from its contact block 40 and twice permit the spring 26 to completean electrical connection.

The cam 29 (Fig. 4) has a depression at 31, and consequently when thecam makes one complete revolution the lever B will be permitted to closean electric circuit only once in such revolution. Similarly, the cam 30has only one depression shown at 32, and consequently the lever O canclose an electric circuit only once in a revolution of cam 30.

The shaft 14 and the cams secured thereto move in a clockwise directionas shown by the arrows in Figs. 4 and 5. By inspection it will be seenthat the cam 29 must move threequarters of a revolution before the leverB can move under the action of its spring 26 95 from the full line tothe dotted line position.

By similar inspection it will be seen that the cam 30 will permit leverC to move from full line to dotted line position as a result of onlyone-quarter of a revolution of said cam. 1

And by reference to Fig. 3 it will be seen that cam 28 permits lever Ato close electrical connections at one-quarter revolution and again atthree-quarters revolution.

It is to be observed that cam 29 permits an electrical connection to bemade only when the roller 27 of lever B comes to the depression orrecess 31. At all others parts of the cam surface the cam is idle, asfar as any efiect upon the making of an electrical connection isconcerned. Similarly, cam 30 has a lever operating recessonly at thepoint- 32, all other parts of the cam surface being non-effective asfaras contact making is concerned. 7

Normally, cams of this kind would be round between the points at thebeginnings and ends of the operative recesses, that is, those parts ofthe cams which did not affect the contact making operations would be atuniform radii from the center of the shaft for'the-sake of economy ofpower and the avoidance of wear. It is to be observed, however, thatthese cams have flat surfaces. That is, each cam is in the form of asquare, with a recess on one side, and the extreme corners cut off. r

Asbefore described, the shaft 14 has on it a ratchet wheel having fourteeth, and the shaft is advanced by a solenoid having considerablepower. When the solenoid is energized, the armature 11 is attractedrapidly, and has a length of movement determined by it coming intocontact with an internal stop as is customary with devices of this kind.

The shaft 14 and parts connected'securely thereto are comparativelyheavy, and the consequence is that they do not stop suddenly when thearmature stops, but have a tendency to-over-run by mere momentum.

The cams 29 and 30 have fiat faces between the cut off corners, and thecenters of these flat faces correspond with the teeth on the ratchetwheel 15. That is, when the ratchet wheel is in the position shown inFig. 2, one orboth of the cams 29 and 30 have the centers of fiat facesin contact with rollers 27. To move the shaft 14 either way from theposition shown in Figs. 4 and 5 would be to de press levers B and Gagainst the force of their springs 26. As a consequence of the,structure set forth, the springs 26, the levers B and G, and the flatfaces of the cams 29 and 30 act to prevent the ratchet wheel and otherrotary parts over running at the termination of a stroke by the armature11.

In the diagram of Fig. 6, M is a reversible motor, P is a push button,and L is a limit switch. The motor M is used to move anything as a door,a gate, or an elevator, first in one direction and later in the other.The limit switch L is simply an electrical connection whichis closedmechanically by the moved object as it reaches the end of its movementin either direction. Its purpose is to stop the motor by bringing aboutan operation which will break the motor circuit.

The diagram shows the parts in their normal or idle position, exceptthat in such posithe motor to open a door or move some other object, asindicated at D in Fig. 6, he presses the button P. Thereupon a currentfrom the source 7 flows as follows :source3334. solenoid10'-35P36source.

This energizes-the solenoid and advances the shaft 14 and cams thereonone step. By this advance, cams 28 and 30 permit levers A and C to closeconnections with their contacts 40 and 37. Thereupon a current flows:source33C37r+38' M39sour ce;

V This starts the motor inthe proper direction to open the door. Thefirst movement of the door opens the switch L, but as this switch is notin the motor circuit, such opening produces no result beyond breakingthe circuit for the solenoid. When this circuit is broken, the armaturefallsback to bring pawll'? into position to engage the next tooth of theratchet wheel, but otherwise accomplishes nothing.

, Asthe door I) or other moved object reaches the end of its destinedmovement, it-closes the switch L, whereupon a new circuit is completed'and a current flows as follows source 33-34solenoid3540 leverA414236source. Thisadvances the cams 28, 29 and 30 another quarter of arevolution, or a total of a half revolution beyond the startingpositions shown'in Figs. 3, 4 and 5. In these positions the levers A, Band C will all be open as shown in full lines in said figures.

What has just been given represents opening a door or moving any otherobject from one position of rest to another position of rest. If theoperator then or later wishes to closethe door, he presses the button Pas before, and another impulse flows thru the solenoid to advance theshaft 14 and cams thereon another quarter revolution. This leaves leversA and B closed, and lever C open. Under these conditions a currentfiows:source33B43,--44M 39source.

This starts the motor inthe reverse direc-, tion. The first movement ofthe door operates to open the switch L, and the final part of the doormovement closes this switch as described before. The consequence of thisprocedure is to send another impulse thru the solenoid to advance thecams so as to leave all levers open at their contact points. Themovement last indicated completes a full revolution of the shaft 14 andleaves the 1,7so,e 12

parts of the apparatus in the position from which they started.

It is to be observed that the contacts closed by the lever A and thelimit switch L are parallel with the contacts closed by the button P. Asa consequence, the solenoid may be operated either by the push button orby the simultaneous closure of A and L. This makes it possible to startthe motor in each of its directions by a single push button instead ofby a complication of two or more buttons in which the operator isobliged to select the desired button from a plurality of buttons. Fromthe description it will be evident that the functions of lever A are toprepare the circuit of the magnet for ultimate closure by the limitswitch, and to break the circuit for the magnet so that the limit switchmay remain closed when all parts are in idle position. Otherwise, thelever A serves no purpose.

In the upper part of Fig. 1 is shown a knife switch for connecting thecircuits shown in Fig. 6 to a source of electrical energy, but as suchswitch is well known, it is not herein described.

What I claim is:

1. In a device of the class described, contact closers, springs servingto move said contact closers to contact closing positions, a shaftprovided with electrical connections for advancing it step by step, andcams on said shaft and serving to open said contact closers bydepressing the springs thereof, said cams having their surfaces soconstructed that the tension of said springs operates thru the cams andthe shaft to prevent the parts over-running at the termination of eachstep of the step by step movement.

2. In a device of the class described, a shaft provided with a ratchetwheel by which it is advanced step by step, cams of polygonal form, eachcam having as many sides as there are teeth in the ratchet wheel, andsprings operating thru the sides of the cams to restrain the parts fromover-running at the end of each step of the step by step operation.

CARL J. ANDERSON.

